12-08-2015, 06:00 PM
US octal valves come loose from their bases frequently but it makes no difference to their operation. PVA ("white" glue or Elmer's) works for reattaching them and isn't strong enough to break the glass. Cyanoacrylate "super glue" has definitely been known to break the glass on 1920s UV-199s. I know of two instances and the owners weren't happy. Glass is weak in tension and the glue can pull it apart. Some epoxies are too strong also. The wrong type, on a rear-view mirror, can pull a divot out of the glass.
